Where Are the Remaining Cosmic MacGuffins in Marvel's Cinematic Universe?

Josh Brolin as Thanos - H 2014
<p>Josh Brolin as Thanos - H 2014</p>   |   Marvel Studios
Where should Thanos be looking for the newly renamed Infinite Six?

In the promo for the Blu-ray of Avengers: Age of Ultron, Marvel subtly renames the MacGuffin of its cinematic universe to date — the Infinity Stones are no more; now they're apparently called the Infinite Six. With Avengers: Infinity War on the horizon for 2018, that only leaves five movies in which to find the remaining stones…. So where should fans be looking?

To date, four of the Infinite Six have shown up: The Tesseract first appeared in Captain America: The First Avenger, and was central to Loki's plan in The Avengers; the Mind Stone showed up at first in The Avengers, and eventually attached itself to the Vision in Avengers: Age of Ultron; the Aether was at the heart of Thor: The Dark World; and the Orb was won over by the power of love in Guardians of the Galaxy.

Based on comparing the colors of the stones seen on screen to the ones in comic book mythology (where they're called the Soul Gems, or the Infinity Gems), the two remaining stones are the Soul gem and the Time gem. When joined together, the six traditionally give the owner complete omnipotence, which can be…problematic in the wrong hands. (Thanos, the villain who's shown up in Avengers, Guardians of the Galaxy and Avengers: Age of Ultron to date, used the six gems to wipe out half of all life in the universe in the 1991 comic book series The Infinity Gauntlet. Don't worry; everyone got better.)

The Marvel movie lineup between now and the first half of Avengers: Infinity War is as follows: Captain America: Civil War, Doctor Strange, Guardians of the Galaxy: Volume 2, the Sony-released untitled Spider-Man movie, and Thor: Ragnarok. The likelihood of a non-core Marvel Studios movie like Sony's Spider-Man featuring a central part of the studio's core narrative is pretty low, even before you get to the fact that Spider-Man and supernatural cosmic stuff don't really mix too well, traditionally, meaning that there are really four candidates for Infinite Six appearances.

Much as Spider-Man doesn't really seem like the right place to drop a cosmic weapon, Captain America: Civil War is similarly out; the movie will already feature almost every Marvel hero to date — and introduce a couple new ones — to earn its place in the Cinematic Universe hall of fame, and watching Iron Man and Cap come to blows because of an ideological dispute feels like an unnatural home for either the Soul or Time gem to appear. (Then again, the same thing could have been said for Captain America: The First Avenger, which featured the first appearance of what comics call the "Space Gem.")

Doctor Strange is a natural home for a gem to appear; it's a new character and so needs a link to the larger mythology, and if there's a better movie to host "the Soul Gem" than Marvel's first supernatural property, I'd be very curious to see what it would be. With James Gunn downplaying the second Guardians of the Galaxy's role in the larger Marvel mythology, that, then, leaves the Time Gem and Thor: Ragnarok — or does it?

Certainly, a mystical object that controls time would give Marvel the ability to have its Ragnarok and eat it, too; all of Asgard could fall, fulfilling the mythical apocalypse of the title, only for time travel shenanigans to allow Marvel to raise it again and bring Thor back to star in the next Avengers movie. But wouldn't it make more sense to leave the final gem until the first Infinity War installment, allowing Thanos to achieve ultimate power and use it immediately, making him more of a threat than a character who'll wait between movies to strike?

Only one thing is for sure: By renaming the Infinity Stones "the Infinite Six," Marvel has given fans a countdown of sorts to get them to 2018's next official Avengers movie. From this point on, everything could be a potential Easter egg — as long as that egg is actually an object of unspeakable power.